<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>多类名使用</title>
</head>
<style>
    .red {
        color: red;
    }

    .size {
        font-size: 30px;
    }
</style>
<body>
<div class="red size">
        迪丽热巴
</div>
</body>
</html>